Missouri regulators say new Ameren data call its models into doubt

This was a follow up meeting of the Clean Air Commission in the wake of the recent findings by AIM Chairman’s Council member Ameren. Once again, the results of the commission’s vote is a big win for Ameren.

From the St. Louis Post Dispatch

State regulators say they can’t tell if Ameren Missouri’s Labadie coal plant is causing air pollution violations, giving the utility more time to measure air quality in Franklin and St. Charles counties before the state could take action to curb the plant’s emissions.

New data gathered by Ameren made the Missouri Department of Natural Resources second-guess its models, which suggested the area was violating sulfur dioxide limits. The DNR considered recommending a “nonattainment” designation, which would start the clock on a plan to curb emissions from the state’s largest source of the pollutant.

But the department ended up agreeing with Ameren that the utility’s new monitoring data called those models into question. Besides, the DNR said it must consider Ameren’s data because of a new state law.

Because of the discrepancy between Ameren’s data and state models, the state’s environmental regulator recommended telling the EPA the area was “unclassifiable.” If that recommendation is accepted by the U.S. Environmental Protection Agency, it could mean years more of data collection before determining if the area is violating federal rules.

The Missouri Air Conservation Commission unanimously adopted the DNR’s recommendation during a meeting Thursday morning in south St. Louis County. There was no public discussion among members of the state-appointed body.

“It’s part of a process of everyone coming together,” Missouri Air Conservation Commission Chairman David Zimmermann said after the vote. “There’s a give-and-take and at the end of the day the EPA has the final decision.”

Ameren says new air monitors near the largest power plant in the state show even the areas with the highest concentrations of sulfur dioxide pollution are below federal limits. But the Sierra Club and the Washington University Interdisciplinary Environmental Clinic argue the monitors have been placed in areas Ameren knows will pick up lower concentrations of the pollutant.

Ameren’s sulfur dioxide emissions have drawn extra scrutiny from the EPA in recent months. The DNR submitted a plan for Jefferson County sulfur dioxide pollution this spring over EPA concerns that it underestimated impacts from two other Ameren plants. Now the DNR must deal with Labadie after a federal judge ordered EPA to study the country’s largest sources of sulfur dioxide emissions.

The pollutant forms fine particles that penetrate the lungs and exacerbate respiratory and cardiovascular conditions, according to the EPA and academic studies.

The EPA must decide by July whether to accept the state’s recommendation or designate the area between Washington, Mo., and Wildwood as in nonattainment.

In its recommendation, the DNR wrote that “collecting more accurate input data would help improve the performance and reduce uncertainties associated with the modeling analysis.”

With different modeling results from environmentalists, Ameren and the DNR, the state agency added that the “varying datasets raise questions” about whether sulfur dioxide concentrations actually violate federal standards, as suggested by its models.

Ameren has argued the state’s model and those from environmental groups are only as good as the datasets they’re based on.

“We’ve said all along that monitoring is the best approach,” said Steve Whitworth, Ameren environmental services director. “We are actually well below the ambient air quality standards.”

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